1. C. Carnevale1, G. Finzi1, E. Pisoni1, P. Thunis2, M. Volta1
The impact of thermodynamic module on the CTM performances: a case study in Northern Italy
C. Carnevale1, G. Finzi1, E. Pisoni1, P. Thunis2, M. Volta1
1Dept. of Information Engineering, Faculty of Engineering, University of Brescia, Italy
2European commission, DG JRC, Institute for Environment and Sustainability

2. Outlines The GAMES modelling system The TCAM model
ISORROPIA/SCAPE2 Thermodynamic modules
Case Study
PM10 performance impact
PM10 chemical composition impact
Conclusion

3. GAMES: Gas Aerosol Modelling Evaluation System
Land use
Topography
Emission inventories
MM5
output
PROMETEO
POEM-PM
Temporal
Profiles
3D wind and temperature fields Turbolence and Boundary Layer parameters
Emission Fields
Boundary and
Initial condition
TCAM
VOC /PM speciation
Profiles
3D concentration
fields
BOUNDY
An air quality modelling
system is composed by (i) a meteorological preprocessor,
simulating the wind and temperature
fields and the turbulence parameters over the domain,
(ii) an emission processor, estimating emission
fields for the emitted species alternative emission
scenarios, (iii) a photochemical model that
describes the transport and the chemical transformations
taking place in the atmosphere.
System Evaluation
Tool
EMEP
output

4. Vertical Transport Deposition
TCAM: overview
TCAM
Horizontal Transport
Vertical Transport Deposition
Gas phase chemistry
Aerosol module
3D wind and temperature fields Turbolence and Boundary Layer parameters
3D concentration
fields
Boundary and
Initial condition
Emission Fields
An air quality modelling
system is composed by (i) a meteorological preprocessor,
simulating the wind and temperature
fields and the turbulence parameters over the domain,
(ii) an emission processor, estimating emission
fields for the emitted species alternative emission
scenarios, (iii) a photochemical model that
describes the transport and the chemical transformations
taking place in the atmosphere.

5. TCAM: Overview Eulerian 3D model Transport Module:
Horizontal: Chapeau Function + Forester Filter
Vertical: Crank-Nicholson hybrid solver based on the vertical diffusivity coefficient
Deposition Module: Wet&Dry
Gas Chemistry:
SAPRC97
IEH solver
Aerosol:
Condensation/Evaporation, Nucleation, Aqueous chemistry (SO2)
21 species, 10 size classes
ISORROPIA/SCAPE2 thermodynamic module

6. Thermodynamic module comparison
Feature
SCAPE2
ISORROPIA-II
Chemical species
NO3-, NH4+, SO4=, Na+, Cl-, Ca+, K+, Mg
Activity coefficients
Pitzer (multicomponent) Zdanovskii, Robinson and Stokes (water)
Bromley/Precomputed table
Temperature dependance
Equilibrium constants, DRHs
Equilibrium constants, DRHs, activity coefficients
Solution of thermodynamic equilibrium
Bisectional
Analitical/Bisectional

7. Simulation domain 95x62 cells 11 vertical layer up to 4000 mt a.g.l.;
6x6 km
POMI exercise

8. Performance Comparison: PM10 Mean Value
Summer
Year
Winter

9. Performance Comparison: PM10 Monthly Trend

10. Performance Comparison: PM10 NMAE
Summer
Year
Winter

11. Performance Comparison: PM10 Taylor Diagram
Summer
Year
Winter
* TCAM_ISO
+ TCAM_SCAPE

12. Inorganic ion evaluation
Station
Summer
Winter
Bosco Fontana* 27 14
Brescia 26 17
Saronno 25
Varese 24 32
* No NH4+ data

13. Performance Comparison: NO3- NMAE
Summer
Winter

14. Performance Comparison: SO4= NMAE
Summer
Winter

15. Performance Comparison: NH4+ NMAE
Summer
NME-Summer
Winter

16. Conclusions PM10 INORGANICS
Mean Value: Similar results (underestimation of measured PM10).
NMAE/Correlation: remarkable differences (SUMMER!), with better performaces obtained through ISORROPIA.
INORGANICS
SCAPE2: (quite) large overestimation of NH4+.
NMAE is lower for ISORROPIA but too few data to state a general behavior!